Fundamentals of two-way time transfers by satellite

Hanson, D. W.

doi:10.1109/freq.1989.68861

Cited by 73 publications

(43 citation statements)

References 9 publications

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“…However, if only a comparison of the optical frequencies is required, the recently proposed two-way method [18][19][20] offers a good alternative with the advantage of simplified experimental apparatus without active components. In this method, the fiber noise is eliminated from the frequency comparison signal by post-processing of the data that were obtained synchronously at both sites in the same way as in the two-way satellite time and frequency transfer technique [21].…”

Section: Introductionmentioning

confidence: 99%

Hybrid fiber links for accurate optical frequency comparison

et al. 2017

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We present the experimental demonstration of a local two-way optical frequency comparison over a 43-km-long urban fiber network without any requirement for measurement synchronization. We combined the local two-way scheme with a regular active noise compensation scheme that was implemented on another parallel fiber leading to a highly reliable and robust frequency transfer. This hybrid scheme allowed us to investigate the major limiting factors of the local two-way comparison. We analyzed the contributions of the interferometers at both local and remote locations to the phase noise of the local two-way signal. Using the ability of this setup to be injected by either a single laser or two independent lasers, we measured the contributions of the demodulated laser instabilities to the long-term instability. We show that a fractional frequency instability level of 10^-20 at 10000 s can be obtained using this simple setup after propagation over a distance of 43 km in an urban area

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Section: Introductionmentioning

confidence: 99%

Hybrid fiber links for accurate optical frequency comparison

et al. 2017

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“…The most precise time transfer technique in use today is TWSTFT [37]. This technique takes advantage of the two-way capability of communication satellites (Comsats) to transmit timing signals in both directions to virtually eliminate the transmission and common instrumentation delays between the two participating sites to transfer time.…”

Section: Two-way Satellite Time and Frequency Transfer (Twstft)mentioning

confidence: 99%

“…Time can be transferred via a number of techniques depending on the application and accuracy required [37][38][39][40][41][42][43][44]. The primary means of accurate time transfer today for operating forces is GPS.…”

Section: Global Time Disseminationmentioning

confidence: 99%

Common Time Reference for Naval Systems

Beard¹,

White²,

Detoma³

et al. 2004

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Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. Z39.18Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Ronald Beard PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S ACRONYM(S) 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S REPORT NUMBER(S) 202-404-7054A Common Time Reference (CTR) is a critical factor in the development of new force capabilities, and perhaps the most difficult to achieve without dependence upon GPS. A technical architecture linking the systems on a common reference framework using their existing time and frequency standards was examined as the most effective approach to achieving interoperable systems. To build an inter-systems architecture within the existing system and platform infrastructure will require a fundamental change in adopting interoperable interfaces and more extensive management of the fabric of technical parameters. The foundation of this new architecture can be built upon the existing infrastructure distributed throughout the legacy and developing systems. The means of providing the elements for this architecture and supporting infrastructure is the objective of this report. The interconnection of assets provides the means for synchronization and coherent system operation.

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“…To cancel the propagation delay, we employ the two-way time transfer (TWTT) technique [1] that was originally used in satellite time and frequency transfer (TWSTFT). Later, carrier-phase TWSTFT (TWCP) [2] was developed to measure the variation of time at a much higher precision.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of wireless two-way interferometry (Wi-Wi)

et al. 2017

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Wireless two-way interferometry (Wi-Wi) is the simplified version of "carrier phase based two-way satellite time and frequency transfer," wherein a wireless communication technology is used instead of a satellite communication technology. We used the carrier phase of a 2.4 GHz ZigBee module to measure the variation of two rubidium clocks at remote sites. Since clocks in the ZigBee module are much less precise than rubidium clocks, the carrier phase of the ZigBee signal cannot be used to compare two rubidium clocks in a simple manner. Using a technique to cancel the clock error of transmitters, we demonstrated picosecond-level precision measurement of the time variation of clocks between two remote systems. This synchronization technique at picosecond-level precision opens the door to low-cost wireless positioning at millimeter accuracy.

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Fundamentals of two-way time transfers by satellite

Cited by 73 publications

References 9 publications

Hybrid fiber links for accurate optical frequency comparison

Hybrid fiber links for accurate optical frequency comparison

Common Time Reference for Naval Systems

Demonstration of wireless two-way interferometry (Wi-Wi)

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